Make PipeWire stream shared through DesktopCaptureOptions (similar to X11 implementation sharing XDisplay) so we can implement better cursor support with our own MouseCursorMonitor implementation. Bug: webrtc:13429 Change-Id: I781482aa29cee0c105c42e5109f28e95dde9881b Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/238174 Reviewed-by: Mark Foltz <mfoltz@chromium.org> Commit-Queue: Mark Foltz <mfoltz@chromium.org> Cr-Commit-Position: refs/heads/main@{#35765}